Serigne Sylla

Université Gaston Berger de Saint-Louis, Sénégal, Sociologie, Faculty Member

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Docteur en sociologie. Spécialités: Sociologie des médias, sociologie du travail et des organisations, socio-anthropologie du religieux.
Phone: +221 77 797 35 05
Address: Saint-Louis, Sénégal

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Papers by Serigne Sylla

Revue Djiboul Périodique : Semestriel

by Serigne Sylla and patrice correa

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Discussions sur la pratique de la sociologie dans les contextes africain et sénégalais

Par Serigne Sylla Serigne Sylla est sociologue, chercheur au Laboratoire GERM rattaché à l'Un... more Par Serigne Sylla Serigne Sylla est sociologue, chercheur au Laboratoire GERM rattaché à l'Université Gaston Berger de Saint-Louis du Sénégal. Spécialiste des médias, des organisations et du religieux, il s’intéresse à l’épistémologie des sciences sociales. Ses publications ont porté sur les relations entre les médias et la religion au Sénégal. Introduction Il est pertinent pour le sociologue de faire une critique des pratiques de son métier. Cette ouverture d’un espace épistémologique critiq..

Champ médiatique et pouvoir religieux : les ambiguïtés d'une relation au concours de l'avènement des médias confessionnels sénégalais

Cette these interroge les relations ambigues entre les medias et le pouvoir religieux au Senegal,... more Cette these interroge les relations ambigues entre les medias et le pouvoir religieux au Senegal, une situation liee au contexte socio-culturel du pays marquee par l’avenement des medias confessionnels au cours des annees 2000. En effet, le champ des medias au Senegal se caracterise par son evolution rapide au moment ou ce pays connait une particularite religieuse avec 96% de musulmans et un pouvoir religieux qui s’oppose au champ mediatique. De maniere recurrente, les medias sont accuses d’etre la cause d’une dynamique societale voire meme d’une crise des valeurs. Ainsi, l’avenement des medias confessionnels est encourage par un pouvoir religieux qui veut avoir ses propres medias. Par consequent, ces derniers definissent leurs lignes editoriales confessionnelles et orientent leurs programmes, bien accueillis par le public, a la vulgarisation et a la defense de leurs pratiques religieuses.

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Le Sénégal à l’heure des médias numériques confessionnels. Le Hizbut-Tarqiyyah et son site Internet, comme reflets de nouveaux lieux de culte virtuels

Émulations : Revue des jeunes chercheuses et chercheurs en sciences sociales, 2017

et son site Internet, comme reflets de nouveaux lieux de culte virtuels Serigne Sylla 1 [Résumé] ... more et son site Internet, comme reflets de nouveaux lieux de culte virtuels Serigne Sylla 1 [Résumé] L'évolution des autoroutes de l'information a permis la naissance des médias numériques. Ainsi, Internet et les autres plateformes digitales se sont montrés comme les nouveaux rois de la communication. Dès lors, ils ont modifié les relations sociales et les institutions comme la religion. Ce qui a encouragé l'émergence des médias numériques confessionnels. Cet article les analyse comme de nouveaux lieux de culte en partant du site Internet htcom.sn du groupe Hizbut-Tarqiyyah. Son contenu est étudié en trois points : islam en général, le mouridisme et les faits sociétaux traités selon le point de vue islamique.

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Recruitment of native parasitoids of the tomato leaf miner Tuta absoluta (Meyrick 1917), (Lepidoptera: Gelechiidae) in Senegal

International Journal of Pest Management, 2021

Invasion de la mineuse de la tomate, Tuta absoluta, au Sénégal: dynamique des populations, plantes-hôtes et ennemis naturels

La detection recente au Senegal de la mineuse de la tomate, Tuta absoluta (Meyrick) (Lepidoptera,... more La detection recente au Senegal de la mineuse de la tomate, Tuta absoluta (Meyrick) (Lepidoptera, Gelechiidae), constitue une serieuse menace pour la perennite de la filiere " tomate " au Senegal. Les larves attaquent le parenchyme des feuilles (mines) mais sont egalement capables de creuser des galeries dans les jeunes tiges et dans les fruits. Le ravageur s'est signale lors des campagnes 2013 et 2014 par la destruction de parcelles de tomate plein champ, en particulier dans la zone de production maraichere des Niayes. L'objectif de l'etude etait de faire le point sur la progression du ravageur a l'echelle du pays, de suivre la dynamique de ses populations dans la zone la plus infestee (hot spot), de recenser les plantes hotes qui permettent a ses populations de se maintenir ou de se multiplier, d'identifier les ennemis naturels indigenes. Le suivi d'un reseau national de 45 pieges a pheromones nous a permis de confirmer sa presence en 2015 sur tou...

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Incidence de deux ravageurs clés des cultures de tomate plein champ dans la zone maraîchère des Niayes au Sénégal

La tomate est l'une des speculations les plus importantes en termes de revenu dans le secteur... more La tomate est l'une des speculations les plus importantes en termes de revenu dans le secteur horticole au Senegal. Neanmoins, sa production rencontre d'enormes contraintes, liees notamment a la pression des insectes ravageurs. La detection recente de la mineuse de la tomate, Tuta absoluta (Lepidoptera, Gelechiidae), constitue meme une serieuse menace pour la perennite de la filiere. L'objectif de cette etude etait (i) d'etablir un diagnostic des principaux insectes ravageurs des cultures de tomate dans la zone maraichere des Niayes, et (ii) d'en evaluer la variabilite spatio-temporelle. Un total de 98 parcelles de tomate, reparties selon un gradient Sud-Nord de la zone des Niayes, a ete suivi sur quatre cycles de culture, d'octobre 2012 a mai 2014. Toutes les trois semaines, du repiquage a la recolte, les insectes ravageurs ou leurs degâts ont ete observes sur 24 plants par parcelle. Le diagnostic montre que la noctuelle de la tomate, Helicoverpa armigera (L...

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First Record of Nesidiocoris tenuis (Reuter) (Heteroptera: Miridae), as a Predator of the Tomato Leaf Miner, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), in Senegal

The recent detection in Senegal of the tomato leaf miner, Tuta absoluta (Meyrick) (Lepidoptera: G... more The recent detection in Senegal of the tomato leaf miner, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) and its rapid geographic spread, is a real concern for tomato production in Africa south of the Sahara. Deployment of effective biological control in the newly invaded area is urgently needed. The predatory species, Nesidiocoris tenuis (Reuter, 1895) (Heteroptera: Miridae), was collected, for the first time in Senegal, from tomato fields infested with T. absoluta. Laboratory feeding bioassay confirmed a potential of N. tenuis as a biocontrol agent of T. absolua. (Resume d'auteur)

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Pratiques phytosanitaires dans la zone maraîchère des Niayes

En Afrique sub-saharienne, les cultures maraicheres constituent une composante essentielle du dev... more En Afrique sub-saharienne, les cultures maraicheres constituent une composante essentielle du developpement agricole. Cependant, les bioagresseurs, en particulier les insectes ravageurs, sont un frein majeur a l'amelioration de la productivite et de la qualite de la production horticole. Pour limiter les pertes de recolte, les producteurs ont recours a la lutte chimique, avec de potentielles derives dans l'utilisation des insecticides, en particulier lorsque ceux-ci perdent leur efficacite suite au developpement de resistance chez les ravageurs cibles. L'objectif de cette etude est de dresser un etat des pratiques phytosanitaires des producteurs dans la zone des Niayes. Pour cela, des enquetes ont ete realisees aupres des producteurs sur un total de 116 parcelles de chou et 98 parcelles de tomate de la zone des Niayes, suivies du repiquage a la recolte. Les resultats de l'enquete montrent une variabilite importante entre producteurs dans la conduite de la protection ...

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Effect of cut seed tubers and pre-germination on potato tuber yield

International Journal of Biological and Chemical Sciences, 2020

Potato (Solanum tuberosum L.) is one of the important vegetable crops in Senegal with the potenti... more Potato (Solanum tuberosum L.) is one of the important vegetable crops in Senegal with the potential to improve the national food supply and economic benefits to smallholder producers. Experiment was conducted from November 2015 to March 2016 to assess the impact of cut seed tubers and pre-germination on seed tuber storage conditions on potato tubers yield. Four treatments were used for experiment. Pre-plant seed treatments were (T1) 136 whole seed tubers 45-55 g then pre-germinated; (T2) 68 cutted tubers 22-28 g then pre-germinated; (T3) 68 pre-germinated seed tubers then cut 22-28 g; (T) 136 whole seed tubers 45-55 g not pre-germinated (maintained 4 °C). Plants grown from whole and pre-germinated seed tubers had significantly higher yield and more number of secondary stems per plant, when compared to cut and or no pre-germinated seed (P < 0.001). Daughter tubers produced from cut seed resulted in higher small size potato tubers than those from whole seed (P < 0.001). However,...

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Insecticide resistance in field populations of the tomato fruitworm, Helicoverpa armigera, from Senegal

International Journal of Biological and Chemical Sciences, 2020

Monitoring of the evolution of insecticide resistance in the field is crucial to prevent pest con... more Monitoring of the evolution of insecticide resistance in the field is crucial to prevent pest control issues. The present study was conducted to assess insecticide resistance status of the fruitworm, Helicoverpa armigera (Hübner) (Lepidoptera, Noctuidae), the most destructive pest of field-grown tomato in Senegal. A sample of 11- 15 field populations were monitored for their susceptibility to abamectin, deltamethrin, and profenofos, using a standard leaf-dip bioassay method. Resistance ratios ranged from 1- to 30-fold to abamectin (4/15 populations with RR>10), 7- to 112-fold to deltamethrin (11/12 populations with RR>10), and 1- to 29-fold to profenofos (3/11 populations with RR>10). This indicates that resistance evolution to deltamethrin was widespread among field populations of H. armigera. However, an increasing trend of resistance to deltamethrin was observed from the South to the North of Niayes. Susceptibility to abamectin and profenofos was generally high but showe...

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Seasonal decline of the tomato leafminer, Tuta absoluta , in the shifting landscape of a vegetable-growing area

Entomologia Experimentalis et Applicata, 2018

Insect pest populations exhibit seasonal dynamics in response to changes in resource availability... more Insect pest populations exhibit seasonal dynamics in response to changes in resource availability or other environmental factors such as climatic conditions, natural enemies, and intra‐ or interspecific competition. Understanding such dynamics is critical for developing effective integrated pest management strategies. The objective of the present study was to identify factors driving the seasonal decline of the tomato leafminer, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), in the shifting landscape of a vegetable‐growing area in Senegal. A set of 42 tomato fields was monitored for the number of T. absoluta adults caught in pheromone traps and for the incidence of larvae, during 5 months from June to November 2016 in the Niayes area (Senegal). The surface of solanaceous host crops, climatic conditions, and abundance of natural enemies were also monitored. A drastic decline in T. absoluta abundance was observed during the rainy season. The decrease in resource availability, especially tomato crops, in the surrounding landscape of monitored fields was the main factor affecting the population dynamics during the rainy season. However, alternative host crops such as eggplant and Ethiopian eggplant, can provide ‘reservoirs’ for residual populations of the pest. For applied purpose, it would be interesting to focus the management efforts on residual populations during the rainy season, to make more difficult the reconstitution of populations during the dry season.

Geographic variation of host preference by the invasive tomato leaf miner Tuta absoluta: implications for host range expansion

Journal of Pest Science, 2019

Host range evolution is a central issue for pest management, particularly for invasive species of... more Host range evolution is a central issue for pest management, particularly for invasive species of agricultural importance. The invasive tomato leaf miner, Tuta absoluta Meyrick (Lepidoptera: Gelechiidae), a key pest of tomato in Europe and recently in sub-Saharan Africa, is a good model organism to better understand underlying processes. We studied oviposition acceptance (proportion of females accepting a given plant as host for laying egg), oviposition preference (number of eggs laid by females on a given host plant) and performance (offspring development estimated as survival from egg to adult) of two T. absoluta populations originating from France (FRA) and Senegal (SEN) on six solanaceous plants (tomato, eggplant, Ethiopian eggplant, potato, sweet pepper and pepper). The ovipositional behavioral pattern differed between the two populations; the SEN population showed higher oviposition acceptance on Ethiopian eggplant and sweet pepper than the FRA population. In addition, SEN population showed higher oviposition preference toward sweet pepper and potato than the FRA population. By contrast, the FRA population showed higher preference toward tomato and eggplant than the SEN population. The two populations of T. absoluta performed best on tomato (the preferred host plant) and showed similar decreasing trend in performance when comparing the two populations on the various other host plants. For both populations, performance on solanaceous plant species was closely related to ovipositional response of females to these plants. The differences observed between the two populations may indicate an ongoing differentiation in the host range of T. absoluta in the two invaded areas, possibly due to the abundance of these alternative host crops in Senegal at a period when tomato crops are scarce.

Arthropod pest complex and associated damage in field-grown tomato in Senegal

International Journal of Tropical Insect Science, 2018

Biotic factors (including insect pests) constrain field-grown tomato production in Senegal. Howev... more Biotic factors (including insect pests) constrain field-grown tomato production in Senegal. However, little information is available on the identity and life system of key pests. The objectives of this study were to: (i) update key pest records of field-grown tomato in the central vegetable-producing area along the northern coast of Senegal, known as the Niayes area; (ii) map their spatial and temporal incidence and (iii) understand insecticide use by growers to control the pests. A total of 98 tomato fields distributed in three zones along a north–south transect in the Niayes area were monitored over four crop cycles from 2012 to 2014. As expected, the tomato fruitworm Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) was the most destructive pest with an occurrence of 92% in sampled fields (90/98) and up to 38% damaged fruits in one field at the time of sampling. The proportion of damaged fruits did not differ among zones, but was significantly higher in the early dry season co...

Occurrence, biology, natural enemies and management of Tuta absoluta in Africa

Entomologia Generalis, 2018

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Spatial and temporal incidence of insect pests in farmers’ cabbage fields in Senegal

International Journal of Tropical Insect Science, 2017

In Senegal, damage caused by insect pests is a major obstacle to seasonal stability and an increa... more In Senegal, damage caused by insect pests is a major obstacle to seasonal stability and an increase in cabbage production. Little is known about the spatial and temporal distribution of cabbage pests, which makes the design of management recommendations to small-scale farmers challenging. The objectives of this study were to: (i) evaluate the status of insect pests observed in cabbage farmers’ fields; (ii) give information on the spatial and temporal distribution of key pests and (iii) assess the effect of temperature, insecticide applications, and host crop abundance on their incidence. A total of 116 cabbage fields were monitored for insect pests and related damage over four crop cycles, from October 2012 to May 2014, in the main vegetable producing area of Senegal (Niayes). The diamondback moth Plutella xylostella (L.) was by far the most important pest present in all the fields and with high levels of incidence (37.1% infested plants), particularly in the latter part of the dry ...

Rapid spread of the tomato leafminer, Tuta absoluta (Lepidoptera: Gelechiidae), an invasive pest in Sub-Saharan Africa

Entomologia Generalis, 2017

Abstract The invasive tomato leafminer, Tuta absoluta (Meyrick) (Lepidoptera, Gelechiidae) has be... more Abstract The invasive tomato leafminer, Tuta absoluta (Meyrick) (Lepidoptera, Gelechiidae) has become a real threat for the continued production of tomatoes across Sub-Saharan Africa since its first detection in Senegal. However, little is known of its geographical expansion, seasonal population dynamics, and damage to crops. A trapping network was deployed in 2014 and 2015 in Senegal to monitor the dynamics of T. absoluta populations at a regional and nationwide scale. A field network was also implemented in the most infested area to get information on the pest incidence during the 2013–2014 cropping season. In 2014, pheromone traps did not detect the presence of T. absoluta moths in remote areas of Eastern Senegal. In 2015, moths were detected in all the fifteen monitored areas deployed throughout the country. Abundance of trapped moths was greatest in 'Niayes', the main tomato-producing area. Unexpectedly, T. absoluta moths were trapped in some areas with few or no tomato crops, including off-season in the 'Vallee du fleuve', hot drylands ('Matam' and 'Kidira') and urban environments ('Dakar'). This suggests high mobility of moth populations and capacity to survive in harsh environments and to persist on alternative host plants. Field monitoring in the main tomato-producing area showed a very low incidence of T. absoluta over the early dry season (0–2% mined leaves), followed by severe outbreaks during the late dry season (up to 60% mined leaves). Results on the invasive pest occurrence will be helpful to decision-makers with a view to develop alternative strategies such as biological control by indigenous natural enemies or collective management strategies based on the temporal or spatial exclusion of host crops. (Resume d'auteur)

Life-History Traits of Macrolophus pygmaeus with Different Prey Foods

PLOS ONE, 2016

Macrolophus pygmaeus Rambur (Hemiptera: Miridae) is a generalist predatory mirid widely used in a... more Macrolophus pygmaeus Rambur (Hemiptera: Miridae) is a generalist predatory mirid widely used in augmentative biological control of various insect pests in greenhouse tomato production in Europe, including the invasive tomato leafminer, Tuta absoluta (Meyrick) (Lepidoptera, Gelechiidae). However, its biocontrol efficacy often relies on the presence of alternative prey. The present study aimed at evaluating the effect of various prey foods (Ephestia kuehniella eggs, Bemisia tabaci nymphs, Tuta absoluta eggs and Macrosiphum euphorbiae nymphs) on some life history traits of M. pygmaeus. Both nymphal development and adult fertility of M. pygmaeus were significantly affected by prey food type, but not survival. Duration of nymphal stage was higher when M. pygmaeus fed on T. absoluta eggs compared to the other prey. Mean fertility of M. pygmaeus females was greatest when fed with B. tabaci nymphs, and was greater when offered M. euphorbiae aphids and E. kuehniella eggs than when offered T. absoluta eggs. Given the low quality of T. absoluta eggs, the efficacy of M. pygmaeus to control T. absoluta may be limited in the absence of other food sources. Experiments for assessing effectiveness of generalist predators should involve the possible impact of prey preference as well as a possible prey switching.

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Invasion of the tomato leafminer,Tuta absolutain West Africa: Spatial dynamics, ecological niche, and potential for biological control

2016 International Congress of Entomology, 2016

Since its first detection in 2012 in Senegal Tuta absoluta has become a severe threat to the prod... more Since its first detection in 2012 in Senegal Tuta absoluta has become a severe threat to the production of tomatoes in West Africa. Objectives of this study were to (i) map the current spatial distribution of the pest in Senegal, (ii) obtain information on population dynamics and damage in the main tomato-producing areas, and (iii) identify alternative host plants and indigenous natural enemies. A trapping network and field survey were implemented from 2013 to 2015 to monitor T. absoluta incidence at a regional and nationwide scale. In 2014, pheromone traps did not detect the presence of T. absoluta moths in eastern Senegal. In 2015, moths were detected in all fifteen monitored areas throughout the country. Abundance of trapped moths was greatest in coastal Senegal, including the main tomato-producing area (Niayes). Unexpectedly, T. absoluta moths were trapped in some areas with few or no tomato crops, including off-season (Vallée du fleuve), hot drylands (Matam and Kidira) and urban environments (Dakar). T. absoluta was also detected in eggplant, Ethiopian eggplant, potato and sweet pepper fields, but not in pepper fields. Laboratory tests showed a positive correlation between larval performance on these host plants and female oviposition preference. Very low larval parasitism (0.4%) was observed whereas predators such as Nesidiocoris tenuis and Orius sp. might be good candidates for biocontrol. Results on the bio-ecology of this invasive pest will be helpful to decision-makers with a view to developing appropriate surveillance and sustainable management strategies.

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